Field
The present invention relates to a method for producing a glassy carbon mold and a method for forming a fine pattern using the same.
Description of the Related Art
In general, production of materials having a variety of micro- and/or nano-patterns is required in fields, such as displays, optical communications, information storage, diagnosis and treatment, drug development and energy, and plastic micro- and/or nano-patterns obtained by a plastic replication process, are predominantly used for low-cost production suitable for the mass-production of such materials. However, it is not easy to utilize plastic products in some applications for various reasons, such as low heat resistance, heat resistance, water resistance and electrochemical properties thereof, and the lack of the type of optical materials. Use of glass or metal micro- and/or nano-patterns is required in applications for which plastic materials are unsuitable.
Among various methods for forming glass or metal micro- and/or nano-patterns, a replication process using a molding press process is known to be the most suitable for mass-production. In this regard, it is considerably important to maintain shape stability, hardness, and corrosion resistance of the mold for a glass molding press used for the glass molding press process at high temperatures (i.e., 300° C. or higher) and high pressures (2.5 to 3.0 MPa), unlike a mold used for polymer replication processes. For this reason, tungsten carbide (WC), aluminum nitride (AlN), titanium nitride (TiN), aluminum oxide (Al2O3), or the like are used as a mold material.
The mold material is a representative difficult-to-cut material and is generally subjected to mechanical working based on grinding to form a mold having a depressed micro- and/or nano-pattern, and the mechanical working does not ideally enable working to a form with a minimum diameter (i.e., generally 10 μm to 100 μm) or less for a working tip. In addition, working costs exponentially increase with the increase of working load due to the properties of mechanical working, and there is thus a limit in the formation of array-type micro- and/or nano-patterns. The fine pattern processing techniques based on semiconductor etching are also used for processing micro- and/or nano-patterns of difficult-to-cut materials, but have increased processing costs due to a low etching ratio.
Accordingly, the development of novel methods for producing micro- and/or nano-patterns at low cost using materials stable under high temperatures and pressures is required in order to provide low-cost mass-production techniques for glass or metal micro- and/or nano-patterns.
Accordingly, as prior art, Korean Patent Application No. 2010-0128786 discloses a method for producing a micro/nano mold for a glass molding press process, including molding a thermosetting resin having a micro/nano structure based on a replication process and carbonizing the thermosetting resin, in order to form a glass structure having a micro/nano structure using a glassy carbon mold material which is produced by carbonizing a thermosetting resin and is useful as a mold material of a glass molding press process due to properties such as high temperature hardness and corrosion resistance.
The conventional method discloses various process techniques (for example, adjustment of a curing agent concentration or addition of an alcohol additive) for controlling various defects (e.g., foams or cracks) generated during the production of an integrated form of a glassy carbon mold that should be produced with a predetermined thickness or higher for application to the glass molding press process, but these process techniques fail to stably secure the superior surface qualities of micro/nano patterns present on the glassy carbon mold. In an approach to solve this problem, additional magnetorheological fluid grinding is suggested. The magnetorheological fluid grinding may be applied to some micro-patterns, but deformations may be generated during the grinding, and magnetorheological fluid grinding is unsuitable for application to nano-patterns and microstructures having complicated shapes.